We have small falcons in So Cal that catch prey and eat them on fences (or in the case of my yard on top of a telephone pole). I think that a bird being the offender is the most logical explanation. If it were me though I wouldn't take any chances, I googled "Protection Spells" and found this for you Wicked. It's on the internet so it must be real.
SPELL FOR PROTECTION
Make a sachet to wear around your neck. The color should be blue or purple but make it
a color you can live with. On the night of a full moon, blend these herbs together:
--amber juniper dill vervain St. John's Wort lavender
by crushing them together with a mortar and pestle. Leaving them in the vessel, hold them
up to catch the light of the full moon and say:
"Moon of night in fullness shine
bless this rite protection be mine"
Then without touching it fill your pouch and wear it whenever you feel threatened.
It also works if you keep it in your pocket.
